I can't get the trainer to work anymore. It just immediately crashes when I press F1 and I have everything on my PC up to date + I followed all the troubleshooting steps. I'm not sure if there was an update or if something changed on my end.

Maybe you are opt-in any beta version? I've just launched the game and the current trainer works fine on my end.

I downloaded the game yesterday, along with the trainer. Both continued to work fine over several on/off points. Rebooting since last night has made it so the trainer no longer works, wherever/however I am in the game when I activate it. I get this error (see pic attached) and the game shuts down. I've not re-installed yet because I can't seem to find my save file, but I did verify the game cache via Steam.